Field of the Invention
The present invention relates to an image forming apparatus capable of executing correction processing.
Description of the Related Art
A high level of color reproducibility is demanded for image forming apparatus in recent years. To meet the demand, an image forming apparatus described in US patent application publication No. 2004/0042807 uses a sensor provided on a sheet conveying path to measure a measurement image formed on a sheet. This image forming apparatus corrects tone characteristics based on the result of the measurement of the measurement image by the sensor. Processing of correcting tone characteristics is hereinafter referred to as “tone characteristics adjustment”.
An image forming apparatus described in US patent application publication No. 2013/0094039 generates a conversion condition for converting image data based on the result of measurement of a measurement image that has a plurality of colors each in a different layer, in order to adjust the colors of a mixed-color image with high precision. Processing of generating the conversion condition is hereinafter referred to as “mixed-color correction”.
In image forming apparatus with this type of sensor installed therein, heat generation from a light emitting unit configured to emit light toward a measurement image causes errors in the measurement value of the sensor. The image forming apparatus therefore raises the temperature of the sensor by emitting light from the light emitting unit of the sensor before the measurement of a measurement image with the sensor. This enables the image forming apparatus to reduce measurement value fluctuations that are caused by changes in the temperature of the sensor itself.
However, there are cases where the image forming apparatus of US patent application publication No. 2013/0094039 executes tone characteristics adjustment and mixed-color correction in succession. The image forming apparatus of US patent application publication No. 2013/0094039 in this case needs to execute optimum preliminary operation of the sensor before correction processing that uses the sensor is executed, to thereby promote energy saving, because the light emitting unit emits light before mixed-color processing is executed despite the fact that the temperature of the sensor prior to mixed-correction is stable.